1. Field of the Invention
The present invention relates to voltage regulators, and more particularly to a digital controller for DC-DC switching converters.
2. State of the Art
The operating principle of a switching converter is known: a high frequency wave (PWFM), generated starting from the input voltage, is successively mediated by means of a passive filter to obtain the desired direct voltage in output. A control system that carries out the measuring of the status variables of the power circuit and consequently regulates the parameters Ton and Toff of the high frequency wave PWFM is needed to keep the value of said voltage stable.
The requirements of the sector for voltage regulators are becoming more and more demanding in terms of current that can be supplied (up to 100 A and up to 400 A is foreseen in the coming years), of reply speed of the system to the load transients and of efficiency which, in the low consumption applications, results in being a fundamentally important specification. In addition there is considerable stimulus towards the reduction of costs and of the shape factor of the output voltage, which involves a reduction of the output filter and thus an increase in the switching frequency, keeping performances high, also for lower current (3/6A) feeds used for dedicated microprocessors, DSP, etc. For the high current applications, attention has recently been concentrated on the multiphase configurations, in which the current capacity of the system is managed by an array of synchronous buck type converters in parallel. Even though nearly all the applications present on the market use analog type controllers, some innovative solutions based on digital control are being widely accepted. The well-known advantages of digital control are capable of satisfying a market that requests more and more complex controllers, low cost applications and an extremely rapid time to market.